(1) Field of the Invention
This invention relates to an electromagnetic shield connection mechanism that brings a shielding portion of a connector into tight electric contact with an equipment side.
(2) Description of the Related Art
In FIGS. 11 and 12, there is shown a conventional electromagnetic shield connection mechanism disclosed in Japanese Patent Application Laid-Open H8-64306. In the mechanism, a cylindrical metal shield (not shown) is inserted into a connector housing 91 made of synthetic resin and a contact piece 93 of the metal shield is exposed from a housing wall 92 at the bottom of the housing 91, thereby allowing the contact piece 93 to contact with an electric equipment 94 (i.e. mating side).
Inside the connector housing 91, there is formed a cylindrical part (not shown) which receives a female terminal (not shown) therein. A terminal base 95 protrudes from the housing wall 92 toward the equipment side for being connected with an electric circuit of the equipment side. On the housing wall 92, there are formed a ring-shaped groove 97 fitting an waterproof packing 96 therein and the contact piece 93 of the metal shield located inside the groove 97.
The housing wall 92 of the connector housing 91 is fixed to the equipment 94 by bolts 98, and simultaneously, the contact piece 93 is brought into contact with a connecting face (grounded) of a wall of the equipment 94. The packing 96 is pressed into the groove 97 of the housing wall 92 and a groove 99 of the equipment 94, thereby waterproofing the contact piece 93 and the terminal base 95. The metal shield prevents noises from coming into the terminal 95. Thus, a direct-mount type connector 100 is composed of the connector housing 91, the metal shield, the terminal and the waterproof packing 96.
However, regarding the above conventional mechanism for electromagnetic shield connection, since the housing wall 92 is made of synthetic resin, the housing wall 92 is bent or deformed due to a repulsion force of the packing 96, and so on, when a significant amount of heat is applied to the housing wall 92 for a long period of time, causing a problem that contact between the contact piece 93 of the metal shield and the contacting face of the wall of the equipment 94 becomes inferior. Even if a spring characteristic is given to the contact piece 93 in order to absorb the deformation of the housing wall, no sufficient contact force is available because of the nature of the material (for example, aluminum alloy) used as the contacting face of the wall of the equipment 94, such as a central processing unit case, i.e. a unit case of an equipment.
In FIG. 13, there is also shown a conventional electromagnetic shield connection mechanism disclosed in Japanese Patent Application Laid-Open H8-64306. In the mechanism, a terminal 102 having wires is received into a cylindrical housing 101 having a flange made of synthetic resin, a cylindrical metal shield 103 is formed into one united body with the housing 101 therein, and a flange of the metal shield 103 is fixed to a wall of an equipment 105 together with a flange 104 of the housing 101 using bolts 106, thereby making a contact between the metal shield 103 and the equipment 105.
A core 113 of a shielded wire 107 is crimp-connected to one side of the terminal 102, and a terminal 109 of a wire 108 of the equipment side is rigidly connected to another side of the terminal 102 using a bolt 110. A braided shield 111 of the shielded wire 107 is connected to the metal shield 103 via a holder 112.
However, regarding the above conventional mechanism for electromagnetic shield connection, since the housing 101 made of synthetic resin lies between the metal shield 103 and the terminal 102, a tightening force by the bolts 106 is deteriorated as the housing 101 and the flange 104 become thin when heat, vibration and impact are applied continuously, causing a problem that a contact between the metal shield 103 and the equipment 105 becomes inferior.
It is therefore an object of the present invention to solve the above-mentioned problems that the contact between the metal shield and the equipment side becomes inferior due to the deformation of the housing wall and/or an oxidation of the connection face of the equipment side, and to provide an electromagnetic shield connection mechanism enabling the secure electromagnetic shielding to be always achieved by improving the contact between the metal shield and the equipment side.